Rotary piston machines have been known which operate as combustion machines. Such machines possess the disadvantage that they expel the burned fuel as an exhaust gas. Such machines, as a result of the exhaust gases they produce, are not favored due to environmental considerations. In stationary machines on the other hand, the exhaust gases must be conducted away over long conduits.
Furthermore, there are rotary piston machines known which are driven with the help of a gas under pressure. Such machines, however, possess the disadvantage that the gas must be stored in a separate device.